all are at 1lb of N per M in a 50lb bag
30-?-? will cover 15M aprox 3 bags per acre, @ 1lb of N per M
32-?-? will cover 16M a little less than 3 bags per acre, @ 1lb of N per M
34-?-? will cover 17M a little less than 3 bags per acre, @ 1lb of N per M
there are aprox 44M in an acre
M =1,000sqft